2.35 Pragma Convention_Identifier

This pragma provides a mechanism for supplying synonyms for existing
convention identifiers. The Name identifier can subsequently
be used as a synonym for the given convention in other pragmas (including
for example pragma Import or another Convention_Identifier
pragma). As an example of the use of this, suppose you had legacy code
which used Fortran77 as the identifier for Fortran. Then the pragma:

pragma Convention_Identifier (Fortran77, Fortran);

would allow the use of the convention identifier Fortran77 in
subsequent code, avoiding the need to modify the sources. As another
example, you could use this to parameterize convention requirements
according to systems. Suppose you needed to use Stdcall on
windows systems, and C on some other system, then you could
define a convention identifier Library and use a single
Convention_Identifier pragma to specify which convention
would be used system-wide.